I currently travel across canada and i have a small repair to do for
a friend the amp is a custom special 100 traynor
the four cathode resistor of the power tube blown
it should be easy to replace them but Im staying in this town
for a limited time and theres no electronic part supply in the region
im relatively new to guitar amp repair but i know theres a lot of desing
that just dont use cathode resistor
can i just bypass them?

I dont Think Traynor uses autobias. If anything they are screen resistors, or something Else. Either way there is probably a reason for the parts to go bad and u need to find that out first. Wavebourn has a good point since it must be something in common to all tubes if all related resistors are blown.